1. Field of the Invention
The present invention relates to a tag attached to the tooling components within a stamping or drawing press, and, more particularly, to a bi-directional RF tag configuration that permits die assembly data to be selectively written to and read from a storage area integral with the tag.
2. Description of the Related Art
Conventional press machines employ a tooling apparatus in the form of a die assembly to shape and arrange a workpiece, such as in a stamping or drawing operation. The die assembly typically includes a lower die attached to a non-movable bed or bolster and an upper die attached to a reciprocating slide. The upper and lower dies, which are installed in opposing spaced-apart relation to one another, cooperate during press machine operation to mutually engage the workpiece at respective sides thereof to thereby effect the desired forming activity.
An essential part of proper machine operation involves configuring the press machine in accordance with the die assembly being used. Die assemblies in general cannot simply be interchanged and then put into use without first giving due consideration to how, and to what extent, the press operating parameters may need to be tailored and adjusted to accommodate the installed die assembly. In particular, each die assembly represents a distinct tooling geometry whose corresponding operating specifications must be recognized by the press controller and formulated into the press operating sequence to guarantee that the machine is rendered fit for the scheduled tooling activity and that the die assembly is effectively used. Accordingly, proper press operation requires, among other things, an identification of the particular die assembly currently installed, any press operating guidelines associated with the die assembly, and the workpiece activity about to the undertaken. Since die assemblies typically do not have a universal or standard machine set-up requirement, each die assembly has associated with it a collection of individual press configuration data sets each correlated to a specific machine and defining the manner in which the press machine needs to be configured to achieve structural and operational compatibility with the die assembly in use. A need therefore exists to provide a facility that supplies the press controller with the proper die-related information before the press operation commences.
One conventional approach to supplying such die information uses an identification-type tag integrally attached to one of the die members and which employs, for example, a bar code or magnetic chip arrangement that embodies a coded data pattern uniquely signifying the die assembly. The identification code constitutes a search-type key used by a central machine processor to locate and retrieve the die assembly information corresponding to the target ID. Such information is typically stored in a memory area associated with the machine processor or at another location remote from the ID tag. These code-type forms of ID tags therefore do not carry or contain the requested die information, but instead function simply to provide an identifying key that points the machine processor to the location (e.g., memory address) of the associated die information.
However, such off-tag placement of the essential die set information means that the ID tag itself becomes useless if for reasons such as system failure or communications breakdown the tag-retrieved code is unable to access the central processing facility that houses the code-indexed die information. Additionally, measures must be implemented within the storage area to preserve the integrity of the large volumes of die assembly data covering all of the usable press machines to protect it from corruptibility. Storing the entirety of the die information in one single location presents serious risks to continued system operability in the event of a catastrophic failure affecting the consolidated die data storage area. A need therefore exists to provide a tag operating independently of the reader device (e.g., machine processor) so that it functions as a content-based source of die information. Such an improved tag would compare favorably to current implementations in which no intrinsic die information is furnished but rather a key is provided for indexing a central storage area.
One alternative approach to utilizing a single, machine-based die data storage area involves incorporating a die set data memory within the tag configuration to store certain types of die information. However, the tag-reader combination, and in particular the proposed die set data memory, are arranged and operated such that the die information is formatted and processed solely in a read-only manner. This choice of using a read-only type of die data storage necessarily limits the type of die information that can be contained within the tag and hence provided to the reader. Only data of a fixed and permanently unchanging character may be stored in such a read-only memory, which prevents the tag from providing the machine processor with a full complement of die assembly data, i.e., both fixed and dynamically variable information, that more fully represents the condition and status of the die assembly.
There exists a wide variety of information pertaining to the die assembly that by its very nature is subject to constant revisioning, such as updatable press reconfiguration requirements and maintenance records critical to proper servicing of the die members. The absence of any data recordation feature relating to die within current tag embodiments information constitutes a drawback for any press machine application that needs to be able to selectively and continuously refresh the recorded die set information with revisions, changes, and/or updates. Without this reprogramming ability, it is not possible to perform such tag-resident tasks as supplementing the existing data with newly developed die information and inserting additional data on reconfiguring the press machine and/or die assembly. Accordingly, a need exists to provide a tag that continues to support a data retrieval function (e.g., a readable memory) but that now permits die information to be selectively revised and recorded therein.
Another drawback of conventional tag units concerns the form of interconnectivity required to establish communications between the tag and reader. The type of interface used in certain tag embodiments such as a bar code or magnetic chip involves a direct physical connection between the components, making access to the tag difficult once the die members are installed. Even if the tag can be suitably accessed, the need for a direct physical connection nevertheless serves as another design consideration that must be taken into account when integrating the tag into the die assembly. A need therefore exists for a system that proposes to eliminate such physical connectivity between the tag and reader device while still supporting communications between the components after installation of the die members and the integrally attached tag.
In one approach designed to alleviate any tag-reader communication problems accompanying the installation arrangement, it has been proposed that access to the tag be undertaken prior to installation while the die assembly is still housed in its magazine. However, this arrangement may not be acceptable if the reader device does not operate in such a portable, mobile fashion but instead is fixedly and integrally secured to the machine in a manner that establishes access with the tag only after installation (e.g., when a line-of-sight communications link is utilized).